This invention relates to medical devices, systems, and methods. In exemplary embodiments, the invention provides an implantable device and system and method for implanting the device within a hollow organ. In other embodiments, the invention provides methods and devices for providing surgical access through a stomach or other tissue.
Electrical stimulation has been used to treat a variety of conditions within the human body. Electrical stimulation of the gastrointestinal tract, such as the stomach, small intestine and colon, have been used to treat a variety of gastric conditions, such as obesity, gastroparesis, gastric dysrhythmia, motility related disorders and nausea, to name a few. Obesity has become one of the leading causes of death in the United States. Electrical stimulation has been proposed to treat obesity by causing a feeling of satiety or reducing desire to eat.
Electrical stimulation has been proposed to treat motility related disorders by influencing contractile behavior. Various organs of the gastrointestinal tract such as the stomach, small intestine and colon contain cells that are believed to govern the organs' periodic contractile behavior. In healthy humans, in certain regions of the organs, these cells generate and propagate rhythmic electrical signals. In general, several types of electrical potential activity have been observed in the gastrointestinal tract. Consistent cyclic slow wave or pacesetter potentials have been observed and higher frequency spike activity has been observed that may correspond to some extent with smooth muscle contractile activity and peristalsis. The stomach and digestive system is also controlled by the nervous system that includes a highly complex enteric nervous system and to some extent, the central nervous system. It is believed that when the pacesetter potentials are combined with a chemical or neural excitation of the cells that smooth muscle contractile activity occurs. It is also believed that stimulation of the stomach may effect a subject's sensation of satiety through a complex system involving smooth muscle stimulation or contractions, and neural and chemical pathways.
An early attempt at a gastric stimulation device included an electrode at the end of a nasogastric tube or catheter. The nasogastric tube was passed into the stomach transnasally. Electrical stimulation was applied using an external stimulator unit through the electrode on the end of the tube. The return electrode was placed on the abdomen. This device required a transnasal procedure whenever stimulation was required.
Other devices used to pace the stomach have generally been implanted by accessing the outside of the stomach through an opening in the abdomen, either through open surgery or laparoscopic surgery. Electrodes have been attached to the stomach laparoscopically with attached leads extending through the abdomen to a subcutaneously or sub-muscularly implanted electronics unit. The devices may be anchored into the subcutaneous or sub-muscular pocket initially by a suture anchor and/or eventually by fibrous tissue ingrowth around the unit.
Endoscopic devices have been presented as an alternative to open or laparoscopic surgery. And example of such devices are described, for example in related U.S. Pat. No. 6,535,764, fully incorporated herein by reference. U.S. Pat. No. 6,535,764 describes a gastric stimulator that is implanted by delivering the device through the esophagus of a subject and attaching to the stomach wall from the inside of the stomach. Also, related U.S. patent application Ser. No. 10/109,296, fully incorporated herein by reference, describes a gastric stimulator that is implanted sub-mucosally within the stomach wall.
It would be desirable to provide improved gastric stimulation devices, delivery systems and delivery methods for an endoscopic approach. Such devices, systems and methods should efficiently access the implantation site through the esophagus, should allow secure attachment of the stimulation device to the organ wall, and should provide desired stimulation to the organ wall. In addition, it would be desirable to provide delivery systems and methods for passing through the organ wall, such as to access the peritoneal cavity and/or fixedly attach devices to the organ wall. At least some of these objectives will be met by the present invention.